U.S. photographic reconnaissance satellite of the Keyhole series. First launched on July 12, 1963, the Gambit series differed from the earlier Corona in being a "close-look" satellite, using the KH-7 camera for clear, detailed photographs of small areas. The Gambit series satellites were developed primarily to provide details of Soviet intercontinental missile installations.
The initial Gambit missions were not fully successful because of problems with the orbital control mechanism, but those problems were soon solved. There were 38 Gambit launch attempts through June 4, 1967 -- almost 10 per year. Two launches failed; the others were successful, with their two film canisters being parachuted down for aircraft in-flight snagging.
